Driers of this type are used, for example, preferably, in the plastics industry in order to dry granulates, as is necessary for the production of plastic bodies in blow-molding methods. It is known to pour the granulate to be dried into a funnel-shaped drier and conduct a current of drying air into the floor region of the drier, which current subsequently rises and removes the moisture from the granulate, and the dry air then escapes through a discharge opening on the top side.
The known drier is operated in circulating air operation. Accordingly, a current of dry compressed air is introduced into the line upstream of a fan, this compressed-air current expanding in the fan and being conducted upstream into the floor region of the drier through this fan via one or a plurality of outlet nozzles.
A disadvantage of the known method and the drier operating in accordance therewith is that a continuous compressed-air current must be made available, which is machine-intensive. This compressed-air current must be filtered, de-oiled and appropriately heated in order to achieve favorable conditioning of the drying air.
A further disadvantage is the relatively machine-intensive requirement for circulating the drying air in the drier in the circulating-air operation. Corresponding lines are necessary for this, as is a suitable fan, in order to assure a constant throughput in circulation through the drier.
A further disadvantage is that the compressed-air current, which is introduced upstream of the fan, cannot be guided and conditioned separately from the drying-air current.
Thus, the disadvantage arises that no separate air current can be fed into the drier, which is advantageous in many drying jobs.
Therefore, it is the object of the invention to modify a method and a drier operating in accordance with the method such that improved drying of the material to be dried is assured with low machine intensity.